纳米纤维素的表面修饰及对聚乳酸膜的力学性能和阻隔性能的影响

本实验通过化学水解法从农林废弃物油茶果壳中提取出油茶果壳纳米纤维素（cellulose nanocrystals, CNC），经丁酸酐表面修饰获得丁酸酯化纳米纤维素（butyrated cellulose nanocrystals, BCNC）后，通过溶液浇铸法制备得到了BCNC/聚乳酸（PLA）复合材料，研究了CNC改性后的形貌及性能变化，以及BCNC对PLA力学性能、阻隔性能及透光率的影响。研究结果表明，经改性后，纳米纤维素的团聚现象得到改善并能稳定的分散在非极性有机溶剂中。在PLA复合材料中，BCNC对PLA有增强增韧的效果，添加5 wt%的BCNC时，PLA膜的拉伸强度提升了30.1%。添加5 wt%的BCNC，PLA复合膜的水蒸气透过率和氧气透过率分别下降了60.0%和35.0%，且仍具有较高的透光率。由于BCNC在基体中有更好的分散性和界面结合，对提升PLA力学性能和阻隔性能的效果均优于CNC。

Influence of Cellulose Nanocrystals on the Mechanical, Barrier and Transparency Properties of Poly( L-lactic) Acid Film

The cellulose nanocrystals (CNC) was extracted from the shell of Camellia oleifera Abel by chemical disintegration method. The butyrated cellulose nanocrystals (BCNC) was prepared by surface modified with Butyric anhydride, and the BCNC/PLA nanocomposites were prepared by solvent casting method. Morphologies and properties of BCNC were observed, and the tensile properties, barrier properties and the transparency of BCNC/PLA nanocomposites film were studied in this paper. The strength and toughness of PLA were improved by composited with BCNC, and the tensile strength of PLA composites film was improved 30.1% by adding 5 wt% BCNC. Adding 5 wt% BCNC, the water vapor gas permeability and oxygen permeability of the film were decreased by 60.0% and 35.0%, and the composite films still maintain high transmittance. Owing to the excellent dispersion and interfacial adhesion in the matrix, the BCNC have a great influence on the tensile properties and barrier properties of PLA than CNC.